Custom validations in rails: validates_number_range


#1

http://sishen.lifegoo.com/?p=42

I don’t know whether there exists a builtin validation that can check
the
number range. I think the requirement is normal, but indeed, i can’t
find
it. So i wrote a custome validation: validates_number_range, whose
prototype is validates_length_of. If there already exists one, pls tell
me,
:slight_smile:

The code is below, welcome to give me any advice on my blog. And also,
more
details information on the blog, :slight_smile:

module ActiveRecord
module Validations
module ClassMethods
def validates_number_range(*attrs)
validates_numericality_of attrs.first
options = {
:too_big => “is too big (maximum is %d)”,
:too_small => “is too small (minimum is %d)”,
:wrong_number => “is the wrong number (should be %d)”
}.merge(DEFAULT_VALIDATION_OPTIONS)
options.update(attrs.pop.symbolize_keys) if
attrs.last.is_a?(Hash)

    # Ensure that one and only one range option is specified.
    range_options = ALL_RANGE_OPTIONS & options.keys
    case range_options.size
      when 0
        raise ArgumentError, 'Range unspecified.  Specify the 

:within,
:maximum, :minimum, or :is option.’
when 1
# Valid number of options; do nothing.
else
raise ArgumentError, ‘Too many range options specified.
Choose
only one.’
end

    # Get range option and value.
    option = range_options.first
    option_value = options[range_options.first]

    case option
    when :within, :in
      raise ArgumentError, ":#{option} must be a Range" unless

option_value.is_a?(Range)

      too_small = options[:too_small] % option_value.begin
      too_big  = options[:too_big]  % option_value.end

      validates_each(attrs, options) do |record, attr, value|
        if value.nil? or value < option_value.begin
          record.errors.add(attr, too_small)
        elsif value > option_value.end
          record.errors.add(attr, too_big)
        end
      end
    when :is, :minimum, :maximum
      raise ArgumentError, ":#{option} must be a nonnegative 

Integer"
unless option_value.is_a?(Integer) and option_value >= 0

      # Declare different validations per option.
      validity_checks = { :is => "==", :minimum => ">=", :maximum =>

“<=” }
message_options = { :is => :wrong_number, :minimum =>
:too_small,
:maximum => :too_big }

      message = (options[:message] || 

options[message_options[option]])
% option_value

      validates_each(attrs, options) do |record, attr, value|
        record.errors.add(attr, message) unless !value.nil? and

value.method(validity_checks[option])[option_value]
end
end
end
end
end
end


#2

If I understood what you are trying to do correctly
validates_length_of :user_name, :within => 6…20, :too_long => “pick a
shorter name”, :too_short => “pick a longer name”

from
http://railsmanual.com/module/ActiveRecord::Validations::ClassMethods/validates_length_of/1.1.2

Matt

Ye Dingding wrote:

http://sishen.lifegoo.com/?p=42

I don’t know whether there exists a builtin validation that can check
the
number range. I think the requirement is normal, but indeed, i can’t
find
it. So i wrote a custome validation: validates_number_range, whose
prototype is validates_length_of. If there already exists one, pls tell
me,
:slight_smile:


#3

No, that’s not i want to do. Sorry, my
blog(http://sishen.lifegoo.com/?p=42)
gives more information, so i gave less information in the mail.

My scenario is that I want to check the uploaded file size, for example,
less than 5M. But what validates_length_of is the size, when is a
fixnum, is
4. So validates_length_of can’t be work for me.

Using validates_number_range, now i can code as below:

validates_number_range :file_size,
:maximum => 5242880,
:message => “you can only upload file less than
5M”,
:on => :create


#4

Today i looked through the validations.rb in rails edge. I’m glad to
find
that validates_numericality_of method already has the support for range
check.

The related options are

  • greater_than
  • greater_than_or_equal_to
  • equal_to
  • less_than
  • less_than_or_equal_to
  • odd
  • even

With these, life are more better, :slight_smile: